Apparatus for effecting operations on a fitting on a high pressure gas main

ABSTRACT

In repairing gas mains, a fixture is clamped to the main at the location of the repair, and a conduit is then joined to the main through a sealed fit. The conduit has a valve which separates the conduit into two compartments, and the end of the conduit is adapted to receive a tool mounting, the valve being opened and a tool passed through the conduit to perform repair operations on the main. The tool mounting is connected to the conduit through a sealed connection, and the tool can be operated through the tool mounting means by an operator so that the repair operation occurs through a sealed conduit. The entire operation occurs with normal operation of the main under its usual operating condition of internal superatmospheric pressure. This superatmospheric pressure can be varied and the present invention contemplates pressure for gas mains in the range of 60 psi - 120 psi, other pressures for other materials such as petroleum, water, etc., varying as desired.

[ Nov. 20, 1973 Primary ExaminerMartin P. Schwadron AssistantExaminer-David R. Matthews Attorney-William R. Coffey [57] ABSTRACT Inrepairing gas mains, a fixture is clamped to the main at the location ofthe repair, and a conduit is then joined to the main through a sealedfit. The conduit has a valve which separates the conduit into twocompartments, and the end of the conduit is adapted to receive a toolmounting, the valve being opened and a tool passed through the conduitto perform repair operations on the main. The tool mounting is connectedto the conduit through a sealed connection, and the tool can be operatedthrough the tool mounting means by an operator so that the repairoperation occurs through a sealed conduit. The entire operation occurswith normal operation of the main under its usual operating condition ofinternal superatmospheric pressure.

1 This superatmospheric pressure can be varied and the present inventioncontemplates pressure for gas mains OPERATIONS ON A FITTING ON A HIGHPRESSURE GAS MAIN Charles William Ray, Ft. Wayne, 7 194-. a V.

[73] Assignee: Emmett O. Bandy, Indianapolis,

Ind.

Aug. 23, 1971 [21] Appl. No.: 174,121

Related US. Application Data [62] Division of Ser. No. 807,846, March17, 1969, Pat.

137/318 B231) 41/08, F16e 41/04 137/317, 318; 29/157.1

References Cited UNITED STATES PATENTS United States Patent Ray [APPARATUS FOR EFFECTING I [75 Inventor:

[22] Filed:

[52] US. Cl. [51] Int.

[58] Field of 2,414,911 1/1947 Temple.....

2,756,486 7/1956 Smith............... 2,838,965 6/1958 Mueller et a1.3,533,424 10/1970 Wedge............. 3,626,576 12/1971 Patented Nov. 20,1973 3,773,067

3 SheetsSheet 1 72 2O 2/ 7O 6O 9 94 H Q /W/ Patented Nov. 20, 19733,773,067

3 Sheets-Sheet f APPARATUS FOR EFFECTING OPERATIONS ON A FITTING ON AHIGH PRESSURE GAS MAIN This Application is a Divisional Application ofCharles William Ray, Ser. No. 807,846, filed March 17, 1969, now US.Pat. No. 3,626,576 METHOD FOR REPAIRING PRESSURE LINES SUCH AS GAS MAINSAND THE LIKE.

BACKGROUND OF THE INVENTION Leakages in service mains are a commonoccurrence. When such leakages occur, the usual procedure is to excavateat the location of leakage where the service line taps into the main,and then seal the main off upstream of the defective service line sothat the repair can be made. At the time that the main is sealed,obviously service is temporarily suspended for all consumers downstreamof the location where the seal is placed in the main to permit repairs.The entire operation as described is time-consuming and an altogetherunsatisfactory method of repairing a main because of the inconvenienceto the consumers and the wasteful nature of the repair. For example, thevalve which is used in effecting a temporary seal of the main is notremovable and becomes a permanent but useless part of the main after therepair operation is terminated. Taking into account the disruption ofservice the number of repair personnel, the time required for effectinga repair, and the wasted parts involved, the total operation must beconsidered totally unsatisfactory under present practices. Nevertheless,the repair operation descried is standard and has been followed for manyyears by utility company repair crews.

While many people are aware of the problems described, little has beendone to advance the state of the art in obtaining a more reliable andadvantageous repair method.

OBJECTS OF THE INVENTION One of the objects of the present invention isto im-- prove the method of repairing leakages from gas mains whereinthe repair can be effected without disrupting normal service to theconsumers downstream of the .defect.

A further object of the present invention is to provide a repair methodof a gas main while it remains fully pressurized and without introducingany element of substantial risk or hazard to the repairmen.

Another object of the present invention is to provide a new and improvedmethod for repairing mains in which the repair is in the form of asimple plug which cuts out the defective service outlet and which doesnot require extensive components which must be permanently secured tothe gas main.

A still further object of the present invention, is to provide animproved method for repairing gas mains which can be performed with arelatively fewer number of repair personnel and which can be carried outin a much shorter time so that the expense of a given repair operationis substantially reduced; and, as a consequence, with the same number ofrepair personnel it is possible to perform substantially greater numberof repair operations in a given period, thus upgrading the overalldistribution network. Of course, the method itself is relatively simpleand can easily be mastered by A repair personnel having only ordinaryskill in this art.

Other objects and features of the present invention will become apparentfrom a consideration of the following description which proceed withreference to the accompanying drawings.

DESCRIPTION OF DRAWINGS FIG. 1 illustrates the section of a gas mainbeing repaired, and with repair apparatus illustrated thereon, a portionof the apparatus being broken away to illustrate the internal structureof the repair apparatus;

FIG. 2 is a side elevation view of the gas main and mounting structure,looking in the direction of the arrows 22 in FIG. 1;

FIG. 3 is a section view taken on line 3-3 of FIG. 1;

FIG. 4 is a view similar to FIG. 1 but showing a main of cast iron andwith an outlet fixture somewhat different from that of FIG. 1 betweenthe main and the service line;

FIG. 5 illustrates the drilling-and-tapping operating tool which isthreadedly joined to the end of the conduit;

FIG. 6 is an enlarged view of the drilling-and-tapping tool; and

FIG. 7 is an enlarged view of the tool which is used for plugging thedrilled-and-tapped opening produced by the tool shown in FIG. 6.

DETAILED EXPLANATION OF THE INVENTION There are generally speaking, twotypes of gas mains which can be repaired in accordance with thisinvention, the one is a steel main and the other is a cast iron main.Essentially the operations are the same in each instance, but there aresome differences which will be pointed out in the following description.

A gas main, designated generally by reference'numeral 10 in FIG. 1 has aservice outlet opening 12 sealed by O-ring seal 13 and surounded by acollar 14 which encircles the main. The collar 14 has a threaded opening15 into which is screw threaded a service outlet fixture 16 including astub-fitting 18 with a threaded plug 20 and an elbow 22 which isthreadedly joined at 26 to the stub fitting 18 and by a sleeve (notshown) to service line 27. Should the service line become defective, thevalve 29 (FIG. 2) at the dwelling or other consumer location, is firstturned off, and this is the only consumer service which is terminatedduring the repair operation. Next, two saddles 38 and 40 are clamped oneon each side of the service outlet as shown in FIG. 1, each saddleincluding semi-circular collars 40, 42 which are hinged together byhinge pins and the two sections are drawn together by means of a bolt 46which passes through aligned openings in flanges 48 and 50 (FIG. 2).

Each saddle has an internally threaded boss 51 which threadedly receivespipe sections 52 and 54 which serve as posts for pads 56 and 58. Aplatform 60 having a conduit 64 welded at 66 to the platform is placedupright over the service outlet and is then secured by means of bolts70, 72"and nuts 76 on the ends of bolts 70, 72 draw the platformdownwardly so that a sealed recess is brought into engagement withshoulder 94 of the fixture 16. Opening 92 of the platform 60 overlies aplug 20 in the fixture l6 and is sufficiently oversized to permitinsertion of the tool to remove the plug 20 and further registers withthe axis of the stub fitting 18 so that other repair operations can beeffected on the body of the main 10.

The conduit 64 has a transverse gate valve with a diaphragm 104 whichseals the lower end of the conduit 64 into a lower sealed compartment103 and an upper compartment 106 which is at times sealed. The diaphragm104 is operated by a stem which passes through a gland packing 107 andis controlled by hand wheel 108.

At the upper end of the conduit 64 is a threaded opening 115 whichreceives a threaded male adapter fitting 116 ofa tool carrier designatedgenerally by reference numeral 120. A handle 114 is used for making thethreaded connection between 116 and 115. The tool mounting 120 includesan elongated plunger rod 130 having a socket end 132 which fits overplug 20 that is unscrewed by turning handle 138. The socket end ismagnetized so that it will retain the plug 20 when it is unthreaded andis then removed.

After 116 and 115 are joined, the gate valve 100 is opened, withdrawingdiaphragm 104 sufficiently so that the rod 130 and socket end 132 can bepassed downwardly through the conduit 64 as indicated by the dotted lineposition in FIG. 1; and after the plug is unthreaded and raisedsufficiently to enter compartment 106 the gate valve is again closedsealing compartment 103 from the compartment 106, and the fitting 116 isunfastened from 115 permitting removal of the plug 20.

The opening 12 is next drilled to a larger size and tapped by means of atool 140 (FlG. 6) and a tooloperating mechanism designated generally byreference numeral 142 (FIG. With the gate valve 110 still closed, thethreaded adapter fitting 144 of tool operating mechanism 142 isthreadedly joined to internally threaded opening 115, this beingaccomplished by means of the irregularly sided flange 146 which can begripped by a wrench. The body 148 of tool 142 has internal threads forreceiving an externally threaded sleeve 150, and a threaded collar 154screws onto the threaded exterior of sleeve 150 and has integral handles156 which are spaced approximately 90 apart. As the handles 156 areturned, it will raise or lower pressure fingers 158 which are pivotmounted on the handles and include extensions 160 which overlie a flange162 of plunger stem 164. The plunger rod 164 has an internally threadedend 165 which receives a threaded adapter 167 of tool 140 having a drill168 and a tap 170 at the end of stem 172. The stem 172 has integrallyformed irregularly shaped sides 174 by which a wrench can be used tomake the connection between threaded end 167 and an internally threadedopening 165 at the end 178 of plunger rod 164.

As the plunger rod 164 passes through sleeve 150 it is sealed bysuitable gland packing (not shown) so that the plunger rod 164 can berotated and moved longitudinally (in an upward and downward directionreferring to FIG. 5) while maintaining a seal between the plunger rod164 and sleeve 150.

After the threaded adapter 144 is threadedly joined to opening 115 thegate valve 100 is opened and the plunger rod 164 is lowered further tobring the end of drill 168 into drilling contact with opening 12 (FIG.1). Downward pressure is exerted on the tool by rotating collar 154through handles 156 whereby the collar 156 and fingers 158 movedownwardly and through the flange 162, the plunger rod and drill 168 arebiased downwardly. The drill 168 is rotated by means of a crank arm 190with a handle 192. After the drilling is completed, the tap 170 is thenpassed through the newly drilled, enlarged opening, and when the tappingis completed the drill and tap are removed upwardly by reversingrotation of the crank 190. The collar 154 is raised by reverse turningthe handles 156 causing the collar 154 to move upwardly on the threadedsleeve 150 and after the tool is raised sufficiently out of compartment103 the gate valve is closed and the threaded adapter 144 is decoupledfrom threaded end of the conduit.

A third tool designated generally by reference numeral 200 in FIG. 7 isthen fitted onto the end 178 of the plunger rod 164 by means of threadedend 202 of stem 204. irregularly sided flange 206 permits use of awrench to effect this coupling. At the end of stem 204 is a magnetizedAllen wrench 208 which carries a set screw plug 210, the set screw plug210 being dimensioned to fit with the enlarged drilled, and tappedopening produced by drill 168 and tap 170. The threaded adapter 144 isrefitted to end 115 and valve 100 is then opened to permit the insertionof plug 210 through the conduit 64 and into the drilled and tappedopening produced by drill 168 and tap 170.

As a result, the original opening 12 is enlarged, tapped, and repluggedsevering the main 10 entirely from service line 27 without venting themain 10 which continues under normal pressure and in full service to allof the other consumers through their respective service lines.

It will be understood that the drill 168 and tap pass not only throughthe conduit 64, but also through the length of the outlet fixture 16 inreaching the openings 12. The conventional fixture 16, therefore, has aninternal diameter large enough to permit the passage of the drill andtap and tool 200 therethrough.

When the operation is completed, the bolts 70 are removed and thesaddles 38, 40 detached from the main 10 thereby removing the repairapparatus described.

For different size mains I provide different size saddles which areselectively joined to the apparatus through the threaded ends of pipes52 and 54. This invention is readily usable with any different sizemains, the only change being a proper selection of the size of thesaddle appropriate to the main size.

It will be apparent, that from the foregoing description, there is norequirement for insertion of a cutoff valve in the main, which, underprevious practice remains with the main and was an expensive item toexpend. I also omit the welding operation previously employed to attachsuch additional parts to the main.

As described, the entire procedure can take place with only two or atthe most three repairmen, and the time required for effecting a repairin the manner described is of much shorter duration than conventionalrepairs in which the main was itself sealed off. A repair operationpreviously requiring three or four men four hours, can now beaccomplished by a two man crew in about one hour.

When the main is a cast iron main and not a steel main, the drilling andtapping occurs through the fixture 214 (FIG. 4), there being a somewhatdifferent arrangement in the tapoff for the service line 27 as com paredwith the tapoff for the service line 27 in a steel main. In this case,there is provided an adapter block 216 which is press-fitted against aseal 218 in the recessed opening 64, and a second seal 218 is providedbetween recessed end 220 of adapter block 216 and flange 220 of fixture214. As indicated by the dottedlines in FIG. 4, the drilling and tappingoccurs at the throat 240 of fixture 214, and it is plugged in the samemanner with a suitably sized plug which fits the dimension of thedrilled and tapped opening. After the apparatus is removed, the fixture214 is then cut off above the throat 240, and the service line is thusseparated from the main.

In all other respects the repair operation is the same as previouslydescribed with respect to uncapping the original plug 20, drilling andtapping and then replugging in proper sequence. The valve 100 isoperated to allow the successive tools to pass through the conduit 64 sothat the main in this instance, as in the previous instance iscontinuously maintained sealed from the atmosphere thereby maintaining acontinuation of service to the downstream consumers.

OPERATION OF THE INVENTION Once a service line 27 has been determined tobe defeetive, an excavation is made to the level of the main 10 at thelocation of tapoff of the service line 27 into the main 10.

The two saddles 38 and 40 are then coupled one on each side of a serviceline outlet saddle 14 and are clamped in place by means of bolt 46. Themounting pipes 52 and 54 are then screwed into threaded bosses 51 andthe platform fixture 60 is then mounted in place through one or theother of its mounting openings 241 (FIG. 3) at whatever angular positionis most convenient for the platform fixture 60. The clamping bolts 70are then passed through openings 241 and through companion opening inmounting pads 56, 58 and are then tightened down to form a sealedconnection between recess 90 and shoulder 94 of the outlet fixturebetween the main 10 and the service line 27.

The threaded end 116 of the tool operator 120 is then screwed into thethreaded open end 115 of the conduit and the gate valve 100 is opened bywheel 108, retracting the diaphragm 104 to the position shown in FIG. 1and the elongated plunger rod 130 is then lowered, bringing the socketended tool 132 into contact with plug 20 and handle 138 is then rotatedto unscrew the plug 20 which is then removed, the socket beingmagnetized to retain the plug 20.

After the plunger 130 is raised together with the tool and attached plug20 and before unscrewing adapter 116 from threaded end 115, the gatevalve is closed by the wheel 108 thus isolating compartment 103 fromcompartment 106. The tool operator 120 is then separated from theconduit by unscrewing adapter 1 16 and in place of socket ended tool, anew tool 140 is attached, by threadedly joining the end 167 (FIG. 6) toend 178, the tool 140 being equipped with the combination drill 168 andtap 170 shown in FIG. 6. After adapter 144 is joined to l 15, the gatevalve 100 is again opened, and by operating handles 156 the collar 154is screwed down causing the fingers 158 to apply downward pressure onthe plunger rod 164 through its flange 162 and causing the drill 168 tobear against the service outlet opening 12. Note that the drill passesnot only through the conduit 64 but also through the length of theoutlet fixture 16 in reaching opening 12 (FIG. 1).

The handle 192 is then rotated to operate the crank arm 190 and rotatethe rod 164, stem 140, and drill 168, thus drilling a larger sizeopening which is then tapped with tap 170.

After drilling and tapping is completed, the handles 156 arecounterrotated raising the collar 154 and detaching the fingers 158 fromthe flange 162 permitting raising of the rod 164 and attached stemtogether with the drill 168 and tap 170 tools. The handle 192 is thenused to raise the tool 140 into chamber 106 and the wheel 108 is thenturned to close the diaphragm 104 sealing compartment 103 from 106 andthe adapter 144 is next decoupled from end 115.

The tool 200 (FIG. 7) having the Allen wrench end 208 with magneticallyattached plug 210 is then fastened to the tool operator 142, and end 144is recoupled with internally threaded opening 115 of the conduit 64. Thegate valve is again operated to an open position and plunger rod 164 islowered to bring the set screw plug 210 into position with the enlargedtapped, opening formed by drill 168 and tap 170. The crank is turned byhandle 192 to screw the set screw plug 210 into position and thenplunger or rod 164 is raised into chamber 106 and adapter 144 siunscrewed from threaded end 115. The saddles 38 and 40 are then removedby unfastening bolts 46 and saddle 14 can also then be removed or can beleft on the main 10. The service line 27 is thus effectively sealed fromthe main while the main 10 remains fully pressurized at all times andconsequently the service to the downstream consumers is at all timesundisturbed.

One of the important values of the present invention is that leakagefrom the main is held at an absolute minimum during the time of reppair;and, consequently, there is substantially less hazard to the repairmen.The opportunities of explosion and wasteful vending of gas is minimizedsince the repair operations are always conducted under closedconditions. Furthermore, the number of servicemen required to carry outthe operations described is substantially less than normally provided,and the operation as a whole can take place within a much reduced periodof time so that the cost per repair operation is reduced. Also, sincerepairmens time is more efficiently utilized, it is possible to upgradethe service network as a whole because a greater number of repairoperations can be performed within a given period of time. I have alsofound, that because the repair apparatus is localized, it does notrequire sealing off of the 'entire ma'in; a smaller excavation isrequired, and this also contributes to a reduced repair time and a moreefficient repair time.

The present invention is applicable not only to gas mains but to otherfluid carrying lines as well, as for example oil pipe lines, watermains, natural gas lines, gasoline and other petroleum product lines. Inshort, any fluid line which it is desired to be repaired can be servicedin the foregoing manner and I intend that the following claims includesuch application within their scope.

It should be further noted, that the only addition to the main is a plug210, whereas previously there was an added expensive valve which had tobe added to the main to seal off the main and become a permanent part ofthe main. There is no corresponding loss of components in the presentinvention; and this also adds to the greater economy of a repairoperation.

In the case of a cast iron pipe repair, where the repair is effectedthrough the outlet fixture, referring to FIG. 4, the plug is firstremoved from the fixture 214. The procedure is the same as removal ofplug 20 in the steel main; but, the boring and tapping take place withinthe outlet fixture 214, this bored and threaded opening then becomingsealed with a replacement plug 210. The outlet fixture to the serviceline is then severed above the throat 240 (FIG. 4), and that is thefinal operation.

Although the present invention has been illustrated and described inconnection with certain selected example embodiments, it will beunderstood that these are illustrative of the invention and are by nomeans restrictive thereof. It is reasonably to be expected that thoseskilled in this art can make numerous revisions and adaptations of theinvention, and it is intended that such revisions and adaptations willbe included within the scope of the following claims as equivalents ofthe invention.

What is claimed is:

1. Apparatus for effecting operations on a fitting on a high pressuregas main, the fitting extending away from the main and a service conduitextending from the fitting and terminating with an end having a circularshoulder, said apparatus comprising mounting means adapted for rigidclamping to said main at the location of the fitting, conduit meanssupported by said mounting means to form a concentric sealed connectionwith the shoulder of the fitting, said conduit means including an accessconduit providing a sealed conpartment enclosing the end of the fitting,valve means disposed in said conduit means and adapted to be opened andclosed to provide access to the fitting through said sealed compartment,tool mounting means having a sealed connection with said conduit meansand forming in combination with said conduit means a second sealedcompartment in communication with said first mentioned sealedcompartment through said valve means, and a tool means operated by saidtool mounting means and movable through said first and secondcompartments when the valve means is opened for access to the fittingfor effecting operations thereon.

2. The apparatus of claim 1 in which said mounting means includes a pairof clamps adapted to be disposed on the main on opposite sides of thefitting, said conduit means including a rigid plate extending betweenand supported on said clamps, said plate being provided with an openingtherethrough in concentric registry with the end of the fitting andcommunicating with said first mentioned sealed compartment, and asealing ring concentrically disposed in said opening peripherally andconcentrically to engage the shoulder of the fitting.

3. The apparatus of claim 2 in which each of said clamps includes asaddle clamp adapted to be rigidly fastened about the main, a mountingpad rigidly sup ported on said saddle clamp, and fastening means forconnecting the adjacent portion of said plate to said pad.

4. The apparatus of claim 3 in which said pads and said fastening meansare disposed, when said fastening means are tightened, to pull saidmounting plate and said sealing ring securely against the shoulder ofthe fit- 8 ting.

5. The apparatus of claim 4 in which each of said clamps includes a postfor rigidly supporting its mounting pad, said post extending generallyparallel to the fitting away from the main.

6. Apparatus for effecting operations on a fitting ex tending outwardlyfrom a high pressure gas main, the fitting terminating with a distal endhaving a circular shoulder and a removable plug concentrically disposedtherein, the fitting defining an internal space in communication withthe interior of the main through an aperture in the wall of the main andwith a service line leading away from the fitting, said apparatuscomprising, a pair of clamps proportioned and designed rigidly to engagethe main on opposite sides of the fitting, conduit means including amounting platform mounted on said clamps and having a through openingtherein concentrically to receive the distal end of the fitting, sealingmeans disposed in the opening sealably to engage the shoulder of thefitting, said conduit means providing a sealed compartment incommunication with said opening at the end of the fitting, valve meansdisposed in said conduit means and adapted to be opened and closed toprovide access to the internal space of the fitting through the sealedcompartment, tool mounting means having a sealed connection with saidconduit means and forming with said conduit means a second sealedcompartment axially outwardly from said first mentioned sealedcompartment and in communication therewith through said valve means, andtool means cooperatively associated with said tool mounting means andmovable through said first and seond compartments when said valve meansis opened for access to the fitting and the interior space thereof.

7. The apparatus of claim 6 including means for mounting said platformon said clamps, said mounting means including a mounting pad rigidlyattached to each clamp, and fasteneing elements for securing saidplatform to said pads.

8. The apparatus of claim 7 in which said pads and fastening elementsare disposed such that, when said fastening elements are tightened, saidplatform is pulled against the fitting to accomplish a tight sealbetween said platform and the shoulder of the fitting.

9. The apparatus of claim 6 in which said tool means includes a magneticwrench for removing the removable plug from the end of the fitting toprovide access to the interior space thereof.

10. The apparatus of claim 9 in which said tool means includes drill andtap means for forming a tapped opening in the wall of the main.

11. The apparatus of claim 9 in which said tool means includes drill andtap means for forming a threaded opening in the throat of the fittingadajcent the main.

1. Apparatus for effecting operations on a fitting on a high pressure gas main, the fitting extending away from the main and a service conduit extending from the fitting and terminating with an end having a circular shoulder, said apparatus comprising mounting means adapted for rigid clamping to said main at the location of the fitting, conduit means supported by said mounting means to form a concentric sealed connection with the shoulder of the fitting, said conduit means including an access conduit providing a sealed conpartment enclosing the end of the fitting, valve means disposed in said conduit means and adapted to be opened and closed to provide access to the fitting through said sealed compartment, tool mounting means having a sealed connection with said conduit means and forming in combination with said conduit means a second sealed compartment in communication with said first mentioned sealed compartment through said valve means, and a tool means operated by said tool mounting means and movable through said first and second compartments when the valve means is opened for access to the fitting for effecting operations thereon.
 2. The apparatus of claim 1 in which said mounting means includes a pair of clamps adapted to be disposed on the main on opposite sides of the fitting, said conduit means including a rigid plate extending between and supported on said clamps, said plate being provided with an opening therethrough in concentric registry with the end of the fitting and communicating With said first mentioned sealed compartment, and a sealing ring concentrically disposed in said opening peripherally and concentrically to engage the shoulder of the fitting.
 3. The apparatus of claim 2 in which each of said clamps includes a saddle clamp adapted to be rigidly fastened about the main, a mounting pad rigidly supported on said saddle clamp, and fastening means for connecting the adjacent portion of said plate to said pad.
 4. The apparatus of claim 3 in which said pads and said fastening means are disposed, when said fastening means are tightened, to pull said mounting plate and said sealing ring securely against the shoulder of the fitting.
 5. The apparatus of claim 4 in which each of said clamps includes a post for rigidly supporting its mounting pad, said post extending generally parallel to the fitting away from the main.
 6. Apparatus for effecting operations on a fitting extending outwardly from a high pressure gas main, the fitting terminating with a distal end having a circular shoulder and a removable plug concentrically disposed therein, the fitting defining an internal space in communication with the interior of the main through an aperture in the wall of the main and with a service line leading away from the fitting, said apparatus comprising, a pair of clamps proportioned and designed rigidly to engage the main on opposite sides of the fitting, conduit means including a mounting platform mounted on said clamps and having a through opening therein concentrically to receive the distal end of the fitting, sealing means disposed in the opening sealably to engage the shoulder of the fitting, said conduit means providing a sealed compartment in communication with said opening at the end of the fitting, valve means disposed in said conduit means and adapted to be opened and closed to provide access to the internal space of the fitting through the sealed compartment, tool mounting means having a sealed connection with said conduit means and forming with said conduit means a second sealed compartment axially outwardly from said first mentioned sealed compartment and in communication therewith through said valve means, and tool means cooperatively associated with said tool mounting means and movable through said first and seond compartments when said valve means is opened for access to the fitting and the interior space thereof.
 7. The apparatus of claim 6 including means for mounting said platform on said clamps, said mounting means including a mounting pad rigidly attached to each clamp, and fasteneing elements for securing said platform to said pads.
 8. The apparatus of claim 7 in which said pads and fastening elements are disposed such that, when said fastening elements are tightened, said platform is pulled against the fitting to accomplish a tight seal between said platform and the shoulder of the fitting.
 9. The apparatus of claim 6 in which said tool means includes a magnetic wrench for removing the removable plug from the end of the fitting to provide access to the interior space thereof.
 10. The apparatus of claim 9 in which said tool means includes drill and tap means for forming a tapped opening in the wall of the main.
 11. The apparatus of claim 9 in which said tool means includes drill and tap means for forming a threaded opening in the throat of the fitting adajcent the main. 